The incidence of hepatitis C virus (HCV) infection increases year by year in China according to Ministry of Health statistics of China. The World Health Organization (WHO) has estimated that at least 2.5-4.9% of China's population is HCV positive. Injection drug use is a main route of HCV transmission. The HCV infection among Chinese injection drug users (IDUs) is high, particularly among those in methadone maintenance treatment (MMT) (e.g., more than 80% in many provinces). Due to share many characteristics, co-infection with HIV and HCV is common. Considering the enormous number of drug users in China, rapid transmission of HCV/HIV among and beyond this population, long duration of clinical progression of the virus, and limited access of infected addicts to routine treatment, HCV/HIV is one of China's major health burdens. Despite the high rate of HCV/HIV infection among IDUs in China, limited HCV/HIV intervention/prevention strategies are available. MMT can provide an efficient platform to address HCV/HIV-related issues among patients, but there is generally a lack of knowledge in HCV/HIV-related issues among both patients and service providers in China. Many materials regarding HCVHIV have been developed in the United States and other countries, but research efforts are needed to integrate and adapt them in Chinese settings and to empirically test the educational program to ensure that it is effective to reduce HCV/HIV risk behaviors and increase HCV/HIV-related services among Chinese addicts. We propose to investigate HCV/HIV knowledge, attitudes, and perceptions among injection drug users and service providers in MMT clinics, and further explore the barriers that impact HCV/HIV-related services and medical care. Based on these findings and HCV/HIV-related materials that have been developed in the United States and other countries, we plan to develop and deliver HCV/HIV education programs to IDUs and MMT staff in MMT clinics, with the long-term goal of developing interventions and services that will be effective preventing and reducing HCV/HIV infection and related risk behaviors among IDUs in China. The proposed project, to be conducted in Shanghai, has the following primary aims: 1) To assess HCV/HIV knowledge, attitudes, perceptions, risk behaviors, and HCV/HIV infection among IDUs in methadone maintenance treatment (MMT), 2) To assess HCV/HIV knowledge, attitudes, and perceptions among MMT staff, and 3) To adapt, develop, and deliver HCV/HIV education programs for clients and MMT staff. Secondary aims are: 4) To explore the barriers that impact IDUs receiving HCV/HIV-related intervention and medical service; 5) To explore ways to facilitate service providers to provide HCV/HIV-related services to IDUs in MMT. The program to be developed and the data collected in the proposed study will establish a basis for developing recommendations of a comprehensive HCV/HIV intervention program to be tested in a future, formal experimental trial. If proven effective, the intervention program can be widely used in China and other countries to reduce HCV/HIV risk behaviors and adverse consequences.